Which plugins have that notification so I can provide the correct download link.

Intel Identity Protection Technology and Google Update. It also says Photo Gallery is unknown but I don't use that.

I just asked another question about Google Update before I realized I could reply here - sorry.

I also have this problem with :-

Google update iTunes application detector Wacom Dynamic Link Library NPCIG.dllCANON iMAGE GATEWAY Mycamera Plugin AdobeExManDetectA plugin to detect whether the Adobe Extension Manager is installed on this machine. AdobeAAMDetectCreative Cloud Desktop Plugin.v_2_0_0_0

Any information would be appreciated.

The Mozilla plugin check website only recognized a few common plugins.
To check plugins that aren't recognized you need to visit its home page and check if there is a newer version.
If a plugin is added by other software then you need to check that software for updates.

If you ever have a question on whether a program or plugin is up to date, all you have to do is to go to the web site of the owner of the program and have the web site check or download the full installer.
For example;

Mozilla programs = Mozilla.org
Real Player Cloud = Real.com
Adobe programs = Adobe.com

And so on.

OK - I'll do that - thanks. I just assumed that Firefox would have the updates like some of the others it has available.

Firefox web sites only has Firefox stuff. Other things like plugins are third party.

Well I went onto a couple of sites to update stuff but on the Wacom site, I updated the driver and it hasn't made a blind bit of difference to the plug in which is still showing as status unknown.

Like I posted above, the Mozilla plugin check page will always show status unknown for plugins that aren't recognized. Updating a plugin won't have any effect on this.